Do we need to kill the growing weeds? Killing the waterhemp and marestail is going to be pricey at this point. If I had those two weeds growing on ground that I wanted to farm next year I would want to kill them and keep them from going to seed. I wouldn't want to do a cover crop that would keep me from controlling those weeds. If I did a summer cover crop I would want to think about weed control in that crop. It doesn't take many weeds going to seed to haunt you for years to come. Not killing those weeds can be pricey for years after they go to seed. I don't know what I would use for a summer cover around here but would want something I could use a preemerge chemical either before or after planting.